Piston ring



Feb. 23, 1954 HslA-sl P1 EN 2,670,256

PISTON RING Filed NOV. 1, 1951 2 Sheets-Sheet 2 2 3 3 /o [zii /a /a Il! /o /o U /a /a 2 Patented Feb. 23, 1954 PISTON RING Hsia-Si Pien, Drexel Hill, Pa., assignor to Wilkening Manufacturing Company, Philadelphia, Pa., a corporation of Delaware Application November 1, 1951, Serial No. 254,345

Claims. l

The present invention relates to a 3piece piston-ring for internal combustion engines and the like and relates more particularly to a springexpanded multi-seal compression ring.

For the purpose of illustrating the invention, there is shown in the accompanying drawings one form thereof which is at present preferred, although it is to be understood that the various instrumentalities of which the invention consists can be variously arranged and, organized and that the invention is not limited to the precise arrangement and organization of the instrumentalities as herein shown and described.

In the accompanying drawings in which like reference characters indicate like parts:

Figure l represents an elevational view of the piston-ring embodying the present invention, partly in section, shown disposed in the ring-receiving groove of a piston.

Figure 2 represents an exploded perspective view of the piston-ring embodying the present invention.

Figure 3 represents a fragmentary plan View of a strip or band of spring-metal from which the spacer and expander is formed, shown in its first stage of development.

Figure 4 represents a section on line 4 4 of Figure 3.

Figure 5 represents a fragmentary plan view of the spacer and expander strip in the second stage of its development.

Figure 6 represents a section on line 6-5 of Figure 5.

Figure 7 represents a fragmentary perspective view of the completed spacer and expander strip after it has been curved or bent into a generally circular formation.

Figure 8 represents an enlarged cross-sectional View of the piston-ring of the present invention disposed in a ring-receiving groove of a piston.

The 3-piece compression ring of the present invention is formed of a pair of relatively thin flat cylinder-contacting ring elements or seals I I and I2 respectively and an intervening spacer and expander I3 of generally T-shaped crosssection with the bottom edge I4 of the T being spaced inwardly slightly from the outer peripheral edges I9 of the seals II and I2 and with the two arms I1 and I8 of the T being disposed within the inner peripheral edges 33 and 34 of the seals II and I2 and forming seal-engaging and seal-expanding lugs or ears.

The spacer and expander I3 is formed of a fiat strip or band of spring metal of suitable thickness as indicated in Figures 3 and 4, and may be spring-steel. The more or 1ess-continuous flat band or ribbon of spring steel or other spring metal is then notched or slotted alternately from opposite edges as by the slots 23 and 24; this being preferably done on a punch press. The slots 23 and 24 are so staggered in relation to each other and are of such length as to leave a more or less corrugated formation as indicated in Figure 3. The slots or notches 24 are deeper than the slots or notches 23. This leaves a successive series of outer circumferentially disposed portions I5 and inner circumferentially disposed portions I5, overlapping each other and connected by means of the transverse legs I0. The inner circumferential portions I6 are then bent alternately in opposite directions to form the lugs Il and I8. The so formed strip is then curled into circular form as indicated in Figures 2 and '7. This can be done by coiling it to suitable diameters and then cutting the individual convolutions to form individual spacers and expanders.

The thickness of the metal of which the spacer and expander is formed is such that combined with the thicknesses of the two sealing rings II and I2, in the assembled and operative condition indicated in Figures l and 8, the compositer 3- piece ring will neatly fit within the widthkof the ring-receiving groove 20, with requisite clearance.

The sealing rings II and I2 are generally continuous except for a gap, and may be so set that the gap will be slightly open or substantially closed in the free or relaxed condition of the sealing members II and I2; bearing or contacting of these sealing elements II and I2 against cylinder wall 22 being dependent primarily upon the outward radial expanding force exerted by the spacer and expander I3 against the inner peripheries 33 and 34 of the seals II and I2.

The spacer and expander I3 is likewise formed with a gap 25, with the free ends 2'I and 28 thereof abutting each other when the spacer and expander is mounted and operatively compressed Y within the ring-receiving groove 26 of the piston.

The circumferential length of the expander I3 is such that when the rings I I and I2 are mounted thereon in the manner indicated in Figures 1 and 8, with the rings II and I2 in contact with the cylinder-wallA 22, the successive corrugations of the expander will be resiliently deformed or compressed slightly or crowded slightly within the confines of the inner peripheries of the rings I I and I2. The expander I3 then, acting through lugs II and I8 thereof, exerts uniformly distributed outward radial expanding force against the rings I I and I2. This outward radial expanding force may be varied by varying the overall circumferential length of the expander as well as by the thickness of the metal thereof and the depth and width of the slots 23 and 24', so as to vary the unit of pressure per unit of contact area between the rings 'l I "and I2 'on the one hand and the `cylinder-Wall -22 on the other hand, to the amount most eiiective for the desired sealing of the piston to the cylinder-Wall against the passage of compressed gases under pressure from the combustion chamber or compression chamber.

The expander I3 is preferably made of spring steel tempered to suitable spring temper, but other resilient spring metal may be used.

The sealing rings or rails il and i2 are also preferably made of steel of suitable ha'rdness. However, the sealing rings or rails Il and l2 may 'also be formed of Vsuitable cast iron. The outer cylinder-contacting peripheral surfaces i3 of the rings II and I2 may be chromium plated.

ILl`he foverall radial width of the composite compression ring is vsuch that the expander 53 will not contacter bottom against the inner wall -`of the ring-receiving .groove when the piston ring is operatively mounted therewithin.

The present invention may be embodied in other specicforms without departing from the spirit or Aessential attributes thereof, and it is therefore desired that the presenternbodiment be considered in all respects as illustrative and not restrictive, reference being had to the appended claims rather than to the foregoing description to indicatethe scope ofthe invention.

`Having thus described the invention, the ollowing vis hereby claimed:

1. A multi-piece springexpanded piston-ring comprising a plurality Aof 4spaced-apart sealing rings, 'and va generally fiat `and generally annular intervening corrugated spacer and expander spring intermediate said sealing rings and spacing them apart, having one complete gap therein to .form 'two separate abuttable ends and having fits corrugations extending to-and-fro in a generally radial direction and being circumferentially compressiblewith its freeends in abutting relation t'o `each other, and having sealengaging lugs at its inner periphery extending ,f

axially therefrom into engagement, alternately, with the inner peripheries ofthe opposed'sealing-rings.

i2. "A multiepiece piston-ring comprising a pair of generally flat split annular sealing rings or" uniform cross-section spaced apart from each other, fa 'generally iiat Vand split generally vannular corrugated and circumferentially compressible spacer and expander spring intermediate said lsealing rings formed of a flat sheet of spring metalnotched inwardly from its 'opposite edges to form the corrugations and having sealengaging lugs bent alternately in opposite direc tions-generally at a right angle to the plane of the :sheet along the inner periphery of ysaid spacer and expander, said lugs being disposed in operative relation to and operatively engaging the inner peripheries of said sealing rings to expand them outwardly; the corrugated sheet spacing the sealing rings in relation to each other and in relation to the ring-receiving groove.

3. A -pi'ece piston-ring 'comprising a generally annular and circumferentially Vresilient and compressible non-bottoming seal-supporting expander having one gap therein interrupting the generally annular continuity thereof and forming two separate abuttable ends and having a pair 4oi spaced land opposed sets of seal-supporting and spacing lands in spaced parallel planes generally at a right angle to the axis of piston-ring and havinginner seal-backing projections extending axially outwardly therefrom alternately in opposite directions substantially beyond the plane of said seal-supporting lands and adapted to engage the respective inner peripher'ies of a corresponding pair voi' -cylinder-contacting seals. and a pair of flat and generally continuons split annular uniform-cross-sectiened :seals disposed on yopposite sides of said seal-supporting expander 'along said `seal-lands thereof with the inner 'peripheries of said seals inoperative 311xtaposition tosaid projections so astobe engaged thereby and to be expanded 'radially outwardly when `said '3-pie'ce pistcn-ringfis 'con-fined within cylinder-'diameter with the ends `l'of 'said sealsupporting expander `in abutting 'relation to each other and with the inner peripher-ies--of-the'seals in -operative `engagement with said projections.

4. A generally `annular Yspacer and expander for multi-piece piston-rings comprising afgeneraily corrugated and circuinferentially com-- pressi'olebody with theeorrugations extending to-and-fro generally in a radial direction,"the inner ends of the successive corrn'gations'being formed with ring-engaging and `ring-expa'nding lugs extending alternately in opposite and gen-- erally axial directions substantially beyond the sides of said body.

i5. A generally annular and circnrn'ferentially compressible resilient spacer and expander for multipiece rings comprising a Igenerally flat corrugated sheet of spring metal with the corrugations formed therein by spaced notches extending into it alternately from opposite Aedges in a generally radial direction, vand ring-engaging and ring-expanding lugs bent in a generally axial direction from the inner ends of said corrngations,I alternately in opposite directions `and substantially 'beyond the sides ofrsaid `spacer and expander.

H'SIA-SI Pl'EN.

References Cited :in the leo this patent VUNITlllD STATES PATENTS Number Name yDate 2,2ll7-3 Engelhardt VMay 5, 1942 2,291,876 Carlton Aug. 4, 1942 2,390,044 Bowers Dec. 4, 1945 

